Trump had kind words for Chinese President Xi Jinping, whom he previously criticized for not doing enough on North Korea -- for "trying very hard" to resolve the crisis.

"He certainly doesn't want to see turmoil and death," Trump said in the interview. "I know he would like to be able to do something, perhaps it's possible that he can't."

US Secretary of State Rex Tillerson said in a Fox News interview Thursday that the Chinese had told North Korea they would impose sanctions on the isolated nation if it carried out another nuclear test.

'Never stop'

Trump's comments come a day after his administration briefed nearly every US senator on the North Korea issue, a rare gathering of the entire Senate at the White House.

Some senators said they were reassured by the hour-long update -- led by Trump's national security advisers -- but learned little new information from it.

North Korea has dominated much of Trump's first 100 days in office, as Pyongyang paraded apparent intercontinental ballistic missiles (ICBMs) and threatened US forces in the region.

On Thursday, a North Korean official told CNN the country's nuclear tests would "never stop" as long as the US continued what they viewed as "acts of aggression."